Cas 1200 a cs mount vari focal lens is a great accessory for any system installer using several boxtype cameras cas 1200 has an f 1 4 auto iris that adjusts automatically to bring flexible light control to box type cameras rendering the highest quality images available this is useful for deployments using the same cameras installed in several different lighting environments like garages warehouse loading docks street monitor and etc in addition ir lens avoids shifts of focus points in